[PATCH v4 1/5] scsi: core: Rework scsi_host_block()

From: Bart Van Assche <bvanassche@acm.org>
To: "Martin K . Petersen" <martin.petersen@oracle.com>
Cc: Jaegeuk Kim <jaegeuk@kernel.org>,
	linux-scsi@vger.kernel.org,
	Adrian Hunter <adrian.hunter@intel.com>,
	Bart Van Assche <bvanassche@acm.org>,
	Mike Christie <michael.christie@oracle.com>,
	Ming Lei <ming.lei@redhat.com>, Ye Bin <yebin10@huawei.com>,
	Hannes Reinecke <hare@suse.de>,
	"James E.J. Bottomley" <jejb@linux.ibm.com>
Subject: [PATCH v4 1/5] scsi: core: Rework scsi_host_block()
Date: Mon, 29 May 2023 13:26:36 -0700	[thread overview]
Message-ID: <20230529202640.11883-2-bvanassche@acm.org> (raw)
In-Reply-To: <20230529202640.11883-1-bvanassche@acm.org>

Make scsi_host_block() easier to read by converting it to the widely used
early-return style. See also commit f983622ae605 ("scsi: core: Avoid
calling synchronize_rcu() for each device in scsi_host_block()").

Reviewed-by: Mike Christie <michael.christie@oracle.com>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Cc: Ye Bin <yebin10@huawei.com>
Cc: Hannes Reinecke <hare@suse.de>
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
---
 drivers/scsi/scsi_lib.c | 18 +++++++++++++-----
 1 file changed, 13 insertions(+), 5 deletions(-)

diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
index 25489fbd94c6..5f29faa0560f 100644
--- a/drivers/scsi/scsi_lib.c
+++ b/drivers/scsi/scsi_lib.c
@@ -2940,11 +2940,20 @@ scsi_target_unblock(struct device *dev, enum scsi_device_state new_state)
 }
 EXPORT_SYMBOL_GPL(scsi_target_unblock);
 
+/**
+ * scsi_host_block - Try to transition all logical units to the SDEV_BLOCK state
+ * @shost: device to block
+ *
+ * Pause SCSI command processing for all logical units associated with the SCSI
+ * host and wait until pending scsi_queue_rq() calls have finished.
+ *
+ * Returns zero if successful or a negative error code upon failure.
+ */
 int
 scsi_host_block(struct Scsi_Host *shost)
 {
 	struct scsi_device *sdev;
-	int ret = 0;
+	int ret;
 
 	/*
 	 * Call scsi_internal_device_block_nowait so we can avoid
@@ -2956,7 +2965,7 @@ scsi_host_block(struct Scsi_Host *shost)
 		mutex_unlock(&sdev->state_mutex);
 		if (ret) {
 			scsi_device_put(sdev);
-			break;
+			return ret;
 		}
 	}
 
@@ -2966,10 +2975,9 @@ scsi_host_block(struct Scsi_Host *shost)
 	 */
 	WARN_ON_ONCE(shost->tag_set.flags & BLK_MQ_F_BLOCKING);
 
-	if (!ret)
-		synchronize_rcu();
+	synchronize_rcu();
 
-	return ret;
+	return 0;
 }
 EXPORT_SYMBOL_GPL(scsi_host_block);
 
